Crotogossamide, a cyclic nonapeptide from the latex of Croton gossypifolius.

A new cyclic nonapeptide, crotogossamide (1), was isolated from the latex of Croton gossypifolius. Its structure was elucidated by use of 1D and 2D NMR and MS and by hydrolysis followed by GC-MS analysis as cyclo(-Gly(1)-Ala(2)-Ser(3)-Gly(4)-Leu(5)-Asn(6)-Gly(7)-Ile(8)-Phe(9)-). This is the first report of a cyclic peptide from a Croton species. The known flavonoids kaempferol 3-O-rhamnopyranoside, quercitrin, and myricitrin were also isolated from the plant latex.